Dialog systems are widely used in the information technology industry, especially as mobile applications for wireless telephones and tablet computers. Generally, a dialog system refers to a computer-based agent having a human-centric interface for accessing, processing, managing, and delivering information. The dialog systems are also known as chat information systems, spoken dialog systems, conversational agents, chatter robots, chatterbots, chatbots, chat agents, digital personal assistants, automated online assistants, and so forth. All these terms are within the scope of the present disclosure and referred to as a “dialog system” for simplicity.
Traditionally, a dialog system interacts with its users in natural language to simulate an intelligent conversation and provide personalized assistance to the users. For example, a user may generate requests to the dialog system in the form of conversational questions, such as “Where is the nearest hotel?” or “What is the weather like in Arlington?”, and receive corresponding answers from the dialog system in the form of an audio and/or displayable message. The users may also provide voice commands to the dialog system so as to perform certain functions including, for example, generating emails, making phone calls, searching particular information, acquiring data, navigating, providing notifications and reminders, and so forth. Thus, dialog systems are now very popular and are of great help, especially for holders of portable electronic devices such as smart phones, cellular phones, tablet computers, gaming consoles, and the like.
One of the core features for many dialog systems is to inform the user if the user receives an email and to read the email to the user if the user requests to do so. However, it is very common for people to receive an overwhelming amount of emails every day including a great number of spam messages and advertisements. In light of this, the dialog system feature for reading emails to the users is not effective and, furthermore, it can be annoying to the users, because the users typically do not want to hear spam messages or advertisements.